Silver halide multilayered color photographic material is making marked progress toward high image qualities. In recent color photographic light-sensitive materials, graininess, sharpness and color reproduction, which are three major requisites for image quality, have been improved to a considerably high level. In the case of color photographs for popular use, for example, color prints or color slides which come to customers' hands, seem to be accepted without particular dissatisfaction.
Among these three requisites for image quality, color reproduction has certainly been improved to provide a pure color. But sufficient improvement has not been made so far and problems still remain unsolved in reproduction of colors which are regarded to be difficult to duplicate in photography. Purple, violet, blue-green and yellow-green, for example, which reflect light having a wavelength longer than 600 nm, are liable to be reproduced as a color quite different from the original, causing disappointment among customers.
The primary factors which affect color reproduction are spectral sensitivity distribution and inter-image effect.
With respect to the inter-image effect which functions in a silver halide multilayered color photographic light-sensitive material, it is known that the so-called DIR compound which forms a developing inhibitor or its precursor by reacting with an oxidation product is added to a light-sensitive material, and that the released developing inhibitor generates an inter-image effect which improves color reproduction by controlling development in other color forming layers.
In addition, an effect similar to the inter-image effect can be provided in a color negative film, by use of a colored coupler in an amount larger than necessary to offset useless absorptions.
However, use of a colored coupler in large amounts raises the minimum density of a film and thereby makes it difficult to judge the correction of color and density in printing. As a result, deterioration in color quality of finished prints is apt to occur.
These techniques contribute particularly to the improvement of color purity in the category of color reproduction. And the so-called diffusive DIR compound, which is widely used for its capability of releasing an inhibitor or its precursor having a large mobility, greatly contributes to the improvement in such color purity.
In contrast with these advantages, the inter-image effect has a problem in that the direction in which it is exerted is difficult to control; accordingly, colors are occasionally reproduced in different hues, though improved in purity. U.S. Pat. No. 4,725,529 discloses a method for controlling the direction of the inter-image effect.
U.S. Pat. No. 3,672,898 discloses a spectral sensitivity distribution appropriate for lessening the fluctuation in color reproduction caused by difference in light sources for photographing. But this cannot be a means to improve the color reproduction of the foregoing less reproducible colors.
Japanese Patent O.P.I. Publication No. 34541/1986 attempts to improve the reproduction of those colors which are difficult to reproduce on color films by use of the inter-image effect, including a combined use of the inter-image effect with the spectral sensitivity distribution, and it seems to be effective to some extent.
The typical attempt disclosed therein is to exert an inter-image effect not only from the respective central wavelengths of a blue-sensitive layer, green-sensitive layer and red-sensitive layer as usually done, but also from regions other than the central wavelengths of the respective layers.
This technique is slightly effective in improving the color reproduction when applied to a limited number of specific colors, but it requires that an inter-image effect generation layer be formed by use of another light-sensitive silver halide, in addition to the ordinary blue-sensitive, green-sensitive and red-sensitive layers. This increases the amount of silver consumed as well as the number of manufacturing processes, and thereby raises the manufacturing cost. In addition, the effect is not necessarily satisfactory.
Japanese Patent O.P.I. Publication No. 183249/1990 discloses a technique to improve the depiction in a red shadow portion by combining a photographing light-sensitive material, whose red-sensitive silver halide emulsion layer is formed to have a spectral sensitivity distribution in a shorter wavelength region, with a printing light-sensitive material containing a pyrazoloazole type magenta coupler having little useless absorption in the red region. The spectral sensitivity distribution of the red-sensitive silver halide emulsion layer disclosed therein is the same as that disclosed in Japanese Patent Examined Publication No. 6207/1974.
Red light is light having reflection in the wavelength region larger than 600 nm; accordingly, shifting the spectral sensitivity distribution of a red-sensitive silver halide emulsion layer to a shorter wavelength region lowers the spectral sensitivity to red light and thereby makes a red color region turbid. Though a pure red light is also made turbid at this time, the drop in purity of the red color is minimized by combination with a printing light-sensitive material containing a magenta coupler having little absorption in the red region. By use of this technique, the depiction in a red shadow region can be reproduced with turbidness, in addition, this mitigates the problem with purple and violet, having reflection on the long wavelength side of the red light region, which are liable to be reproduced tinged with red. However, this technique is inadequate for blue-green, which is still reproduced in a different color.
For example, the blue-green having a spectral reflection distribution shown in FIG. 1 is seen as blue-green close to green to human eyes, but it turns blue with little green tinge when reproduced by use of this technique.